Electric furnace.



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Specification for Design.

application ined February 1a, i914. serial No. 819,341.

" .To all whom t may concern:

4 4Beit knownthat l, SIGMUND GUeonN HEIM, a citizen. of the Republic of `fflwitzerland, residing at Bei'lin-llllniersdorf, Germany, have invented a new and useful lm provement in Electric Furnaces Operated byA Eddy-Currents, of which the following is a specification.

My invention' relates to an electric furnace in which the material operated upon, which may be a metal, metallic ore or other suitable substance becomes the seat of eddy currents which are produced in said material by a suitable arrangement of fluctuating magnetic circuits.

In'an application for a patent filed in lGermany, September 3G, i912, l ,have described an electric furnace of the character i thus referred to. ln said .furnace l -place the material to be melted 1n a suitable receptacle and then arrange said receptacle so that it is located in the air gap of two or moreelectro-magnetic circuits. These circuits may be energized by connecting them to any suitable alternating current network.

By thus providing two or more :magnetic circuits, the lines of force respectively due thereto will mutually induence one another so as to pass to a very considerable degree through the body of the material to be melted in which there is thereby established what maybe termed eddy current centers.

.l large amount of energy is in this way injected into the material as contrasted with the amount possible where only one magnetic circuit (one air gap) is employed, for

in this latter case lbut few of the lines get much within the surface (skin etlect). A

large amount of energy is in this'way injected into the materials.

lt is the object of this, my present inven-l tion, 'to improvethe arrangement thus referred to and as described in my German application, by enabling a still greater introduction `and concentration of magnetic lines to be effected' in the cody of the material, thereby making" the melting operation still more economical.

More specifically it is the object of my invention to provide an arrangement comprising three separate "magnetic circuitsuconnected respectively in the three individual conductors Aof a three phase alternat1ngcircuit, or, as it is'o'tten called, rotary circuit. The windings of the separate magnets are suitably soarranged, as regards one another, that the magnetic phases do not agree l with the current phases. 0r, a plurality of groups of three 'circuits as a base maybe v used within the spirit of the invention.

My invention will be better understood by referring to the drawing, in which- Patented Oct. 26, 1915.

Figure 1 shows, diagrammatically, both the current and the magnetic phases in ai.I

'three phase circuit, when the magnetsareI similarly wound and connected; Fig. 2 is a view similar to Fig. showing the magnetic phases lwhen the magnets are sirmlarly wound, but one is reversely connected as re`f gards the others; Fig. v3 represents, diagrammatically in side elevation, a furnace provided with three magneticl circuits according to my invention; Fig. 4 shows the furnace' of Fig. 3 in plan, and Fig. 5 is a plan View from below of the furnace of Fig.

v 3 showing the windings and `connections of the magnets and there is shown in addition a special phasedisplacing arrangement on their current supply .flows in the same sense,

ergy intended for it. lf, however, incon.

necting the several magnetic. circuits, the windingsof one of them be reversed, as rega rds those of lthe other two circuits, as is indicated diagrammatically in Fig. 5, where two ofthe windings e and e2 are joined in the same sense, but oppositely from that of e3, then the magnetic phase of circuit 3 will be displaced 18Go 'from normal. That is to differently connected, I may have-them dify erently wound', but similarly connected. jFurthermore, I ain not confined to connectsay the three magnetic phases will be 60" apart, as indicated in Fig'. 2, instead of 120. apart, as indicatedin Fig. 1. By this arrangement a much larger number of lines of force4 will go through thematerial from onepole of a given circuit to the other, than is the case when .the phases are 120 apart, as indicated in Fig. l.' Besides, or' instead of having the windingsof one magnet circuit reversed, as regards those ofthe other 'tWo,-I may, if I prefer, insert an inductive.' or ohmic resistance in one of said circuits,

or diierent inductive or ohmic resistances in dierent circuits. Or, instead of having the three magnetic circuits similarly wound and.

ing my several magnetic circuits with a three phase circuit, but may, if I desire, conygnect the circuits with' any suitable alternat- The only require- 4 energized by the phase vcfa polyphase curu rent that some of the magneticl'phases will be iinequally displaced.

2. An electric furnace comprising, in combinatiom three electromagnets 'each provided with an' air gap, a receptacle located so as to be in each of said gaps and identilcal windings upon each of said magnets one" of said windings being reversely arranged, "however, as regards those or the other two magnets, said windings being adapted to be respectively, normally connected in the respective conductors of a three phase alterv nating network so that the magnetic phases are different from the electrical phases.

' 3. -An electric furnace comprising, in combination, three electromagnets each provided `with an air gap, a receptacle located so as to be in each of said gaps and windings upon said magnets, said windings having dierent characteristics so thatV when energized by a three phase alternating curunequally displaced.

In testimony whereof I have hereunto set *my hand in the presence'of two subscribing witnesses.

SIGMUND GUGGENHEIM. Witnesses WOLDEMAR 'Hacen I-IENRY4 I-IAsPER.

, rent network the magnetic phases .will be 

